# Relationship history for MSHA mine 4500675

Current hierarchy: **Taiheiyo Cement Corp → Glacier Northwest → Steilacoom Pit**

- Valid-time bounds: inclusive, date granularity
- Null end: open-ended in the upstream history row; not independent proof of present control
- Transaction-time observation: 2026-10-13T11:19:05.459773+00:00

## Valid-time edges

- **operator_operates_mine:** Lone Star Industries Inc → Steilacoom Pit; 1950-01-01 to 1984-03-11; source msha-controller-operator-history
- **controller_controls_mine:** Lone Star Industries Inc → Steilacoom Pit; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Lone Star Industries Inc → Lone Star Industries Inc; 1950-01-01 to 1984-03-11; source msha-controller-operator-history
- **operator_operates_mine:** Pioneer Construction Materials Company → Steilacoom Pit; 1984-03-12 to 1986-02-17; source msha-controller-operator-history
- **controller_controls_mine:** Riedel International Inc → Steilacoom Pit; 1984-03-12 to 1986-02-17; source msha-controller-operator-history
- **controller_controls_operator:** Riedel International Inc → Pioneer Construction Materials Company; 1984-03-12 to 1986-02-17; source msha-controller-operator-history
- **operator_operates_mine:** Northwest Aggregates Company → Steilacoom Pit; 1986-02-18 to 1987-04-08; source msha-controller-operator-history
- **controller_controls_mine:** Riedel International Inc & Lonestar Industries Inc → Steilacoom Pit; 1986-02-18 to 1987-04-08; source msha-controller-operator-history
- **controller_controls_operator:** Riedel International Inc & Lonestar Industries Inc → Northwest Aggregates Company; 1986-02-18 to 1987-04-08; source msha-controller-operator-history
- **operator_operates_mine:** Northwest Aggregates Company → Steilacoom Pit; 1987-04-09 to 1987-12-31; source msha-controller-operator-history
- **controller_controls_mine:** Lone Star Industries Inc → Steilacoom Pit; 1987-04-09 to 1987-12-31; source msha-controller-operator-history
- **controller_controls_operator:** Lone Star Industries Inc → Northwest Aggregates Company; 1987-04-09 to 1987-12-31; source msha-controller-operator-history
- **operator_operates_mine:** Glacier Northwest → Steilacoom Pit; 1988-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Taiheiyo Cement Corp → Steilacoom Pit; 1988-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Taiheiyo Cement Corp → Glacier Northwest; 1988-01-01 to current/open; source msha-controller-operator-history